Towards an Automatic Determination of Grasping Points Through a Machine Vision Approach

In intravenous fluid injection wherein a syringe needle and surrounding sheath are inserted into a vein so that blood flows through the needle into a transparent hollow push-pull element fixed on the needle remote from its point to indicate proper vein insertion, and the needle is then withdrawn from the sheath and from a vial on the end of the sheath through an opening in the vial so that blood back-flows into the vial before intravenous fluid is introduced through the vial and sheath into the vein, apparatus for preventing blood leakage from the vial opening wherein the opening is covered with an elastomeric diaphragm through which the needle is initially pierced and which resiliently self-seals when the needle is withdrawn therefrom, and further wherein intravenous fluid is introduced through a port in the vial separate from the opening covered by the diaphragm, the vial having a substantially fixed volume which remains substantially unchanged during operation, so that upon withdrawal of the needle from the sheath and vial through the vial opening any leakage of blood out of the vial opening is prevented by the diaphragm.